JPS60261233A - Detecting system of control channel disturbing wave - Google Patents

Abstract

PURPOSE:To watch generation of disturbing wave at all times without interrupting service and improve the capacity of the system by making each base station stop transmission of control signals periodically and simultaneously and detecting the disturbing wave during the while. CONSTITUTION:Control signals of the same radio frequency are simultaneously transmitted from plural base stations 2, 3 having respective radio zone 10 by control of a circuit control station 1 of a mobile radio communication system. The control signals are received by a control channel receiving station 4 and presence or absence of disturbing wave is detected. The result of detection is transferred to the control station 1 by a fixed circuit 9. Control signals are inputted by repeaters 12 of base stations 2, 3, and output of the repeaters 12 is applied to an output gate 13 of the signals. The control signals are processed by a synchronism detector 15 and a bit counter 16, and the gate 13 is controlled by the output. Transmission of control signals is stopped by base stations 2, 3 periodically and simultaneously, and disturbing wave is detected during the while. Thus, disturbing wave is watched at all times without interrupting service.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a mobile radio communication system suitable for car phones, mobile phones, etc., in which the service area consists of a plurality of small radio zones, and each small radio zone is This relates to a mobile radio communication system in which a base station is installed in the area, and a control channel dedicated to communication connection control in addition to communication is provided in all small hot-wire zones using a common frequency.

[Conventional technology]

In conventional mobile radio communication systems where a service area is made up of multiple radio zones, such as for car phones, when control signals are transmitted from the same frequency from each base station, interference radio waves on the same frequency as the control channel may occur. When this occurs, some or all of the mobile stations in the service area may recognize it by issuing a control signal.

[Problem that the invention seeks to solve]

However, conventionally, since each base station constantly transmits control signals, the control station cannot recognize the generated interference radio waves separately from the control channel of the base station.
It was impossible to detect the occurrence of jamming radio waves.

Therefore, when attempting to confirm the presence or absence of jamming radio waves and their source, there is a problem in that it is necessary to stop the service and conduct an investigation.

The present invention aims to improve this problem, and aims to provide a method that can detect the occurrence of interference radio waves on a control channel within a service area without interrupting service.

Hereinafter, its structure and operation will be explained in detail based on the drawings of the embodiments.

〔Example〕

FIG. 1 is a conceptual diagram of one embodiment of the present invention, in which 1 is a line control station, 2 and 3 are base stations, 4 is a control channel receiving station, and 5 is a conceptual diagram of an embodiment of the present invention.
, 6 is a fixed line for control signal transmission, 7 is a control channel radio signal transmitted from base station 2, 8 is a control channel radio signal transmitted from base station 3, and 9 is a control channel radio signal transmitted from base station 3. A fixed line 10 for transmitting the results of interference detection represents a wireless zone.

If the base station 2 or 3 can receive the control channel of the other base station, the control channel receiving device may be provided within the base station of the base station 2 or 3 without providing the control channel receiving station 4.

In FIG. 1, control signals transferred to line control station 1 or 6 by base station 2.3 through fixed port 415.6 are transmitted from base stations 2 and 3 via a radio control channel.

This is received by the control channel receiving station 4, the presence or absence of interfering radio waves is detected, and the detection result is transferred to the line control station 1 via the fixed line 9.

FIG. 2 shows a time chart of the control signals in the above embodiment, and the observation points (,) to () in FIG.
d), (a) is a control signal transmitted from line control station 1, (b) is a control signal transmitted from base stations 2 and 3 to the common 5 radio control channel, and (c) )
is a novel received by the receiving station 4, and (d) is a signal sent from the receiving station 4 to the control station 1 to notify the presence or absence of interfering radio waves.

In addition, in the tIS2 diagram, F is a signal frame for synchronization, T is a time slot in which base stations 2 and 3 stop transmitting, S is a signal frame transmitted simultaneously from both base stations, and U
represents the level of interference waves.

Figure 3 shows one of the control signal relay sections in base station 2 or 3.
FIG. 2 is an example block configuration. In the f53 diagram, 11
is a control signal input terminal of the control station 1, 12 is a control signal repeater, 13 is a signal output date, 14 is a control signal output terminal to the transmitter, 15 is a synchronization signal detector, 16 is a pitto counter, Reference numeral 17 represents a signal output terminal for controlling transmission on/off of the transmitter. - The operation of the base station will be explained below with reference to FIGS. 2 and 3.

The control signal transmitted from the control station 1 to each base m2.3 is provided with a synchronization signal F indicating a time slot for simultaneously stopping transmission at each base station 2, 3.
In step 3, the position of the time slot at which transmission is to be stopped is determined based on this synchronization signal.

That is, since the length of each control signal is usually unified, each base station 2, 3 uses this synchronization signal as a synchronization signal detector 1.
5, by starting the bit counter 16, the bit counter 16 started at the same time as the synchronization signal detector 15 can determine the position of the time slot at which transmission is to be stopped. This closes the signal output gate 13 and at the same time sends out a control signal from the signal output terminal 17 to put the transmitter in a transmission stop state. When the end of the required time slot is detected by the bit counter 16, the signal output date 13 is opened and at the same time a control signal is sent from the signal output terminal 17 to put the transmitter into a transmitting state. The 7-rem signal shown in FIG. 2 is repeatedly transmitted from the control station 1 to each base station at the same time, and each base station periodically synchronizes with the above method and turns on the transmitter.
10FF will be repeated.

As a result, the transmission of control signals will be periodically paused, but the pause time is sufficient for several tens of milliseconds to several hundred milliseconds, so there will be no problem with the transmission of control signals. .

FIG. 4 is a block diagram of an example of a jamming wave detection unit in the control channel receiving station 4, in which 18 is a control signal input terminal from the receiver, 19 is a synchronization signal detector, 20 is a bit counter, and 21 is a 22 represents the output date of the signal, and 23 represents the output terminal of the signal that notifies the control station 1 of the presence or absence of interfering radio waves.

The operation related to detecting interference radio waves will be explained below with reference to FIGS. 2 and 4.

Here, "jamming radio waves" are radio waves that are transmitted at the same frequency as the radio control channel common to each base station, and due to the generation of these radio waves, some or all mobile stations transmit data using the FI1 control channel. This refers to something that may prevent the correct reception of control signals. The method of detecting this interference is to identify whether the control signal can be received correctly or not, or to receive the same channel when all base stations have stopped transmitting the radio control channel, and check the reception level. Possible methods include detecting

In the former method, the source of the interference is the control channel receiving IS! 4 and the level of the interfering radio waves is not high enough to erroneously confuse the content of the control signal, the interference radio waves cannot be detected, and therefore, the interfering radio waves cannot be detected accurately.

In the present invention, the latter method is performed periodically without interrupting the service to accurately detect interference waves.

The control channel receiving station 4 receives a control signal as shown in FIG. The station informs the signal output date 22 of the start and end times of the time slot at which it stops transmitting control signals. By opening the date only when this time slot is open, the output date 22 outputs to the control station 1 the presence or absence of the reception level in the time slot in which each base station has stopped transmitting.

The control station 1 receives the J:9 result on the fixed line 9, and if it receives a signal with a reception level as shown in Figure 2(d), it will know that interference waves are occurring in the vicinity of the receiving station. be able to.

By arranging the control channel receiving stations 4 as described above at various locations within the service area, the control station 1 can constantly monitor the occurrence of jamming radio waves and detect the occurrence of interference.

If the receiving station 4 receives strong interference radio waves, the control signal will not be received correctly, and therefore the synchronization signal detector J5 will not be able to receive the synchronization signal.

For such cases, the synchronization signal detector 15 has a built-in timer, and if the synchronization signal cannot be identified for a certain period of time, the output date 22 is opened.
Transmits a signal with a reception level of jamming waves.

〔Effect of the invention〕

As explained above, in the method of the present invention, each base station periodically stops transmitting control signals at the same time and detects jamming waves during that time, so that jamming waves are constantly detected without interrupting service. It has the advantage of being able to monitor, and by installing a plurality of reception stations for monitoring jamming waves, it has the advantage that it is possible to estimate where the jamming waves are occurring at the line control station.

[Brief explanation of the drawing]

Fig. 1 is a conceptual diagram of an embodiment of the present invention, Fig. 2 is a time chart of control signals in the embodiment of the present invention, Fig. 3 is a block diagram of an example of a control signal relay section, and Fig. 4 is a control signal relay section. FIG. 3 is a block configuration diagram of an example of a jamming wave detection section in a channel receiving station. 1... Line control station, 2, 3... Base station, 4... Control channel receiving station, 5, 6...
. . . Fixed line for control signal transmission, 7 . . . Radio signal of control channel transmitted from base station 2, 8 . . .
. . . Radio signal of control channel transmitted from base station 3, 9 . . . Fixed line for transmitting the result of interference radio wave detection at control channel receiving station 4, 10 . . .
・Wireless zone, 11... Control signal input terminal from control station 1, 12... Control signal repeater, 13
......Signal output date, 14...Control signal input terminal to transmitter, 15...Synchronization signal detector, 16...Bit counter, 17・・・・・・
... Output terminal for controlling transmission on/off of the transmitter, 18
...Control signal input terminal from receiver, 19...
...Synchronization signal detector, 20...Bit counter, 21...Input terminal for notification signal indicating presence/absence of reception level from receiver, 22...Signal Output date, 23... Output terminal agent for the signal that notifies control station 1 of the presence or absence of jamming radio waves Patent attorney Hon Q. Takashi Figure 2

Claims (1)

[Claims] In a mobile radio communication system configured to simultaneously transmit control signals of the same radio frequency from multiple base stations each having a radio zone under the control of a line control station, each The base station is provided with a means for periodically pausing the transmission of control signals, and also detects a radio signal with the same frequency as the control signal near the boundary of each radio zone or within the radio zone, and transmits the detection result to the line control station. 1. A control channel interference radio wave detection method, characterized in that the control channel interference radio wave detection method is characterized in that the interference radio wave is identified based on the detection result during a pause in the transmission of the control signal.